Is it considered a sin for a mother to communicate with or help her brother, especially after he caused trauma to her deceased father?

We advise overlooking what happened in the past, and the mother should not refrain from caring for her nephew if she is able to; he is like her own son, and there is a great reward in it. As for the maternal uncle, he may have wronged his father, and it is necessary to forget this matter and be keen on strengthening family ties and kinship.